1. Field of the Invention
The present invention relates to a recording tape cartridge which rotatably accommodates in a case a single reel onto which a recording tape such as a magnetic tape or the like is wound, and is principally utilized as a recording/replaying medium for computers and the like.
2. Description of the Related Art
Magnetic tape cartridges which accommodate in a case a single reel onto which a magnetic tape is wound, and which are principally utilized as a recording/replaying medium for computers and the like, have been known in the prior art. A leader member, which is to say a leader pin, a leader tape, a leader block or the like, is provided at a distal end of such a magnetic tape. The leader member is drawn out through an opening aperture of the magnetic tape cartridge by drawing-out means provided at a drive device side. Thence, the magnetic tape to which the leader member is fixed is wound around a drive device side winding reel.
A reel gear is formed in an annular shape at the middle of a lower face of the reel, and is exposed through an opening hole formed in a lower face of the magnetic tape cartridge. A driving gear provided at a drive device side rotation shaft meshes with the reel gear. Thus, in this structure, the reel is driven to rotate. Consequently, the reel of the magnetic tape cartridge and the winding reel of the drive device are rotated contemporaneously. Hence, data can be recorded to the magnetic tape, and data recorded at the magnetic tape can be replayed.
Such magnetic tape cartridges can be kept in a small accommodation space at a time of storage, and can record large volumes of information. As shown in FIGS. 10 to 12, the position of the opening aperture, and the type of a door that opens and closes the opening aperture is different for each of the different types of leader member. Specifically, in the case of a leader pin 110, as shown in FIG. 10, an opening 118 is formed in a side wall 114 of a case 112. The side wall 114 is parallel with a loading direction into a drive device (the direction of an arrow P). The opening 118 is opened and closed by a door 116, which slides to move in the same direction as the loading direction.
However, if the opening 118 is provided in the side wall 114 of the case 112 in this manner, the drive device side drawing-out means must turn the leader pin 110 around from a left-right transverse direction of the case 112 to draw out the leader pin 110. Therefore, a space for the drawing-out means to turn around must be reserved at the drive device side, and a mechanism for turning around of the drawing-out means is complicated. Thus, the drive device will become larger, which is disadvantageous. Moreover, there is a further problem in that a drawing-out path of a magnetic tape 111 becomes longer.
Alternatively, in the case of a leader tape 120, as shown in FIG. 11, an opening 128 is formed in a front wall 124 of a case 122. The front wall 124 intersects the direction of loading into the drive device (the direction of arrow P). A door 126 opens and closes the opening 128. The door 126 is a rotating-type door which rotates forward about a support shaft 125 which supports the door 126 at a corner portion vicinity of the case 122. However, when the opening 128 is provided in the front wall 124 of the case 122 in this manner, although there is no need for drive device side drawing-out means to turn around, the door opens forward by a large amount. Therefore, it is necessary to reserve space at the drive device side, such that no part of the drive device impedes the door 126 when the opening 128 is opened. Thus, the drive device becomes larger, and this is disadvantageous.
Furthermore, in the case of a leader block 130, as shown in FIG. 12, an opening 138 is formed by diagonally cutting away a corner portion 134 at a front side in the direction of loading into the drive device. The opening 138 is directly opened and closed by the leader block 130. However, when the leader block 130 opens and closes the opening 138 in this manner, there is a problem in that the leader block 130 will tend to become damaged or soiled. That is, the leader block 130 fits into a drive device side reel hub 136, and structures a portion of the reel hub 136. Therefore, damage and soiling that would not be a problem for usual use as a door make it difficult to fit the leader block 130 with the reel hub 136, and there is a risk that running of the magnetic tape 111 may be disadvantaged.
Moreover, the leader block 130 is anchored only at peripheral portions of the opening 138. Therefore, it is easy for the leader block 130 to come out if the magnetic tape cartridge is dropped, which is disadvantageous. In addition, the size of the leader block 130 is large in comparison to the leader pin 110. Therefore, there is a problem in that constraints on the form of the case are numerous. Thus, the leader pin 110, from which the function of the door is separated, is superior to the leader block 130, which is combinedly used as the door.